“Data from this study will be key to securing approval for
the use of the Diamondback 360 Coronary Micro Crown OAS in the world’s
two largest atherectomy markets. We anticipate that the 30-day data from
this study will be presented in calendar 2016.”

The company’s fourth-quarter revenues increased 22 percent to $48.5
million, from $39.6 million in the fourth quarter of fiscal 2014.
Coronary product revenues grew 189 percent to $9.4 million, while
peripheral product revenues grew 7 percent. Customer reorder revenues
remained strong at 96 percent of total revenue, compared to 98 percent a
year ago. While up significantly, revenue was slightly below guidance,
primarily due to sales headcount being below the levels targeted in the
company’s sales optimization and expansion plan during the quarter.

David L. Martin, CSI’s President and Chief Executive Officer, said,
“Significant progress continued on our sales optimization plan in the
fourth quarter. Cross training of our sales force to sell both
peripheral and coronary products advanced with over 140 representatives
now trained. Productivity goals were also achieved per representative,
further validating that our dual application sales approach will provide
attractive growth and lead to profitability in the future. The related
sales force expansion, however, fell short of our targets, resulting in
an average of approximately nine open positions during the quarter. As a
consequence, revenue was slightly below our expectations. We have taken
actions to reach our planned sales force level by the end of the fiscal
2016 first quarter and beyond.”

CSI’s fiscal 2015 fourth-quarter gross profit margin increased to 78
percent from 77 percent. Net loss was $(8.7) million, or $(0.27) per
common share, compared to a net loss of $(9.6) million, or $(0.31) per
common share, in the fiscal 2014 fourth quarter. Adjusted EBITDA loss
improved to $(4.1) million compared to $(5.9) million a year earlier.
Overall, expense levels were lower than anticipated, primarily due to
fewer sales representatives on board than expected.

Fiscal year 2015 revenues rose to $181.5 million, up 33 percent from the
prior fiscal year. Peripheral product revenues grew 17 percent, while
coronary product revenues reached $28.5 million in the first full year
of commercialization. Gross margin increased to 78 percent compared to
the prior-year’s 77 percent. Operating expenses rose 26 percent,
reflecting planned investments, including sales force expansion and
training, and coronary product commercialization. Adjusted EBITDA loss
decreased by $(5.6) million to $(15.6) million, while the net loss
totaled $(32.8) million, or $(1.04) per common share, compared to
$(35.3) million, or $(1.25) per common share, in fiscal 2014.

FDA Clears New Peripheral DevicesCSI continues to develop
enhancements to its product line to further advance its leadership in
treating calcified artery disease. In April, CSI announced that it has
received FDA clearance for the new 4 French (4 Fr) 1.25 Solid
Diamondback 360® Peripheral Orbital Atherectomy System (OAS)
for the treatment of PAD.

Said Martin, “Last year we secured FDA clearance for our 60cm peripheral
devices, which allows for new physician options to access sites in the
foot, allowing physicians to more easily treat challenging lesions in
the lower leg. This new clearance further expands our minimally invasive
product portfolio with longer and enhanced devices. Physicians now have
the ability to treat PAD below the knee through as small as 4 Fr access
sites in the groin, or to treat the upper leg from foot access sites.”

In July, CSI secured another FDA clearance for its new ViperWire Advance®
Peripheral Guide Wire with Flex Tip for use with the Peripheral OAS. The
new guide wire provides physicians with improved flexibility, navigation
and ease-of-use—particularly in hard-to-reach, tortuous vessels—when
treating arterial calcium associated with PAD.

CSI anticipates launching ViperWire Advance with Flex Tip in August
2015. The guide wire is for use with CSI’s 145cm Stealth 360®
and Diamondback 360® Peripheral OAS. For more information on
ViperWire, click here.

COAST Coronary Study Enrollment CompletedIn July, CSI
announced that it has completed enrollment for its Coronary Orbital
Atherectomy System Trial (COAST) study. This study took place in both
Japan and the United States, and was designed to assess the safety and
efficacy, as well as economic outcomes, of CSI’s new Diamondback 360
Coronary Micro Crown Orbital Atherectomy System (OAS) in treating
severely calcified coronary lesions in patients suffering from Coronary
Artery Disease (CAD). As designed, a total of 100 patients were enrolled
in the study.

Martin noted, “Data from this study will be key to securing approval for
the use of the Diamondback 360 Coronary Micro Crown OAS in the world’s
two largest atherectomy markets. We anticipate that the 30-day data from
this study will be presented in calendar 2016.”

Enrollment of patients in this study remains on track with nearly 1,000
patients enrolled. CSI is currently enrolling up to 1,200 patients in
this study, which is expected to be completed in early calendar 2016.

Fiscal 2016 First-Quarter OutlookMartin said, “We begin
fiscal year 2016 as the market leader in atherectomy. Our unique,
low-profile Diamondback 360 is the device physicians rely on to reduce
calcified plaque and improve patient outcomes. We look forward to
completing the optimization and expansion of our sales organization to
drive further OAS adoption and help treat the millions of patients
suffering from PAD and CAD.”

Revenue growth of 23 percent to 27 percent over the first quarter of
fiscal 2015, excluding Asahi guide wire sales in the prior period, to
a range of $48.5 million to $50.0 million;

Gross profit as a percentage of revenues of approximately 79 percent;

Operating expenses approximately 12 percent higher than the fourth
quarter of fiscal 2015, primarily due to expansion of the sales force
and timing of sales meetings and training; and

Net loss in the range of $(12.0) million to $(12.9) million, or loss
per common share ranging from $(0.38) to $(0.40), assuming 32.0
million average shares outstanding.

Conference Call Today at 3:45 p.m. CT (4:45 p.m. ET)Cardiovascular
Systems, Inc. will host a live conference call and webcast of its fiscal
fourth-quarter results today, August 5, 2015, at 3:45 p.m. CT (4:45 p.m.
ET). To access the call, dial (877) 201-0168 and enter the access number
77041031. Please dial in at least 10 minutes prior to the call. To
listen to the live webcast, go to the investor section of the company’s
website, www.csi360.com,
and click on the webcast icon.

For an audio replay of the conference call, dial (855) 859-2056 and
enter 77041031. The audio replay will be available beginning at 6:45
p.m. CT on Wednesday, August 5, 2015, through 10:59 p.m. CT on
Wednesday, August 12, 2015.

Use of Non-GAAP Financial MeasuresTo supplement CSI's
consolidated condensed financial statements prepared in accordance with
U.S. generally accepted accounting principles (GAAP), CSI uses certain
non-GAAP financial measures in this release. Reconciliations of the
non-GAAP financial measures used in this release to the most comparable
U.S. GAAP measures for the respective periods can be found in tables
later in this release immediately following the consolidated statements
of operations. Non-GAAP financial measures have limitations as
analytical tools and should not be considered in isolation or as a
substitute for CSI's financial results prepared in accordance with GAAP.

About Peripheral Artery Disease (PAD)As many as 18 million
Americans, most over age 65, suffer from PAD, which is caused by the
accumulation of plaque in peripheral arteries (commonly the pelvis or
leg) reducing blood flow. Symptoms include leg pain when walking or at
rest. Left untreated, PAD can lead to severe pain, immobility,
non-healing wounds and eventually limb amputation. With risk factors
such as diabetes and obesity on the rise, the prevalence of PAD is
growing at double-digit rates.

Millions of patients with PAD may benefit from treatment with orbital
atherectomy utilizing the Stealth 360and Diamondback 360
Peripheral Orbital Atherectomy Systems, minimally invasive catheter
systems developed and manufactured by CSI. These systems use a
diamond-coated crown, attached to an orbiting shaft, which sands away
plaque while preserving healthy vessel tissue — a critical factor in
preventing reoccurrences. Balloon angioplasty and stents have
significant shortcomings in treating hard, calcified lesions. Stents are
prone to fractures and high recurrence rates, and treatment of hard,
calcified lesions often leads to vessel damage and suboptimal results.

About Coronary Artery Disease (CAD)CAD is a
life-threatening condition and a leading cause of death in men and women
in the United States. CAD occurs when a fatty material called plaque
builds up on the walls of arteries that supply blood to the heart. The
plaque buildup causes the arteries to harden and narrow
(atherosclerosis), reducing blood flow. The risk of CAD increases if a
person has one or more of the following: high blood pressure, abnormal
cholesterol levels, diabetes, or family history of early heart disease.
According to the American Heart Association, 16.3 million people in the
United States have been diagnosed with CAD, the most common form of
heart disease. Heart disease claims more than 600,000 lives in the
United States each year. According to estimates, significant arterial
calcium is present in nearly 40 percent of patients undergoing a
percutaneous coronary intervention (PCI). Significant calcium
contributes to poor outcomes and higher treatment costs in coronary
interventions when traditional therapies are used, including a
significantly higher occurrence of death and major adverse cardiac
events (MACE).

About Cardiovascular Systems, Inc.Cardiovascular Systems,
Inc., based in St. Paul, Minn., is a medical device company focused on
developing and commercializing innovative solutions for treating
vascular and coronary disease. The company’s Orbital Atherectomy Systems
treat calcified and fibrotic plaque in arterial vessels throughout the
leg and heart in a few minutes of treatment time, and address many of
the limitations associated with existing surgical, catheter and
pharmacological treatment alternatives. The U.S. FDA granted 510(k)
clearance for the use of the Diamondback Orbital Atherectomy System in
peripheral arteries in August 2007. In October 2013, the company
received FDA approval for the use of the Diamondback Orbital Atherectomy
System in coronary arteries. To date, nearly 210,000 of CSI’s devices
have been sold to leading institutions across the United States. For
more information, visit the company’s website at www.csi360.com.

Safe HarborCertain statements in this news release are
forward-looking statements within the meaning of the Private Securities
Litigation Reform Act of 1995 and are provided under the protection of
the safe harbor for forward-looking statements provided by that Act. For
example, statements in this press release regarding (i) the expected
optimization and expansion of our sales organization; (ii) the
expectation that our hybrid sales strategy will provide attractive
growth and lead to profitability in the future; (iii) the expectation
that we will reach targeted headcount by the end of the first quarter of
fiscal 2016 and beyond; (iv) the expected benefits and timing of the
commercial launch of new products; (v) the LIBERTY 360° trial, including
the number of patients expected to be enrolled and the timing of
enrollment; (vi) the COAST trial, including the number of patients
expected to be enrolled, the timing of enrollment, the potential to
secure approval of the new micro crown OAS in the U.S. and Japan, and
the expected timing of presentation of study data; (vii) anticipated
revenue, gross profit, operating expenses, and net loss; and (viii)
potential future growth of CSI, are forward-looking statements. These
statements involve risks and uncertainties that could cause results to
differ materially from those projected, including, but not limited to,
our ability to manage employee turnover, growth and training; dependence
on market growth; the reluctance of physicians, hospitals and other
organizations to accept new products; the experience of physicians
regarding the effectiveness and reliability of CSI’s products; actual
clinical trial and study results; the potential for unanticipated delays
in enrolling medical centers and patients for clinical trials; the
impact of competitive products and pricing; the difficulty to
successfully manage operating costs; fluctuations in quarterly results;
agreements with third parties to sell their products; regulatory
developments in the U.S. and foreign countries; FDA and international
regulatory clearances and approvals; approval of our products for
distribution in foreign countries; approval of products for
reimbursement and the level of reimbursement; general economic
conditions and other factors detailed from time to time in CSI’s SEC
reports, including its most recent annual report on Form 10-K and
subsequent quarterly reports on Form 10-Q. CSI encourages you to
consider all of these risks, uncertainties and other factors carefully
in evaluating the forward-looking statements contained in this release.
As a result of these matters, changes in facts, assumptions not being
realized or other circumstances, CSI's actual results may differ
materially from the expected results discussed in the forward-looking
statements contained in this release. The forward-looking statements
made in this release are made only as of the date of this release, and
CSI undertakes no obligation to update them to reflect subsequent events
or circumstances.

Product Disclosures:

Peripheral ProductsThe Stealth 360® PAD System
and Diamondback 360® PAD System are percutaneous orbital
atherectomy systems indicated for use as therapy in patients with
occlusive atherosclerotic disease in peripheral arteries and stenotic
material from artificial arteriovenous dialysis fistulae. The systems
are contraindicated for use in coronary arteries, bypass grafts, stents
or where thrombus or dissections are present. Although the incidence of
adverse events is rare, potential events that can occur with atherectomy
include: pain, hypotension, CVA/TIA, death, dissection, perforation,
distal embolization, thrombus formation, hematuria, abrupt or acute
vessel closure, or arterial spasm.

Coronary ProductIndications: The Diamondback 360®
Coronary Orbital Atherectomy System (OAS) is a percutaneous orbital
atherectomy system indicated to facilitate stent delivery in patients
with coronary artery disease (CAD) who are acceptable candidates for
PTCA or stenting due to de novo, severely calcified coronary
artery lesions.

Contraindications: The OAS is contraindicated when the ViperWire
guide wire cannot pass across the coronary lesion or the target lesion
is within a bypass graft or stent. The OAS is contraindicated when the
patient is not an appropriate candidate for bypass surgery, angioplasty,
or atherectomy therapy, or has angiographic evidence of thrombus, or has
only one open vessel, or has angiographic evidence of significant
dissection at the treatment site and for women who are pregnant or
children.

Warnings/Precautions: Performing treatment in excessively
tortuous vessels or bifurcations may result in vessel damage; The OAS
was only evaluated in severely calcified lesions, A temporary pacing
lead may be necessary when treating lesions in the right coronary and
circumflex arteries; On-site surgical back-up should be included as a
clinical consideration; Use in patients with an ejection fraction (EF)
of less than 25% has not been evaluated. See the instructions for use
before performing Diamondback 360Coronary OAS procedures for
detailed information regarding the procedure, indications,
contraindications, warnings, precautions, and potential adverse events.
For further information call CSI at 1-877-274-0901 and/or consult CSI’s
website at www.csi360.com.

Caution: Federal law (USA) restricts this device to sale by or on
the order of a physician.

Micro Crown OASCSI has commenced its COAST Investigational
Device Exemption clinical trial to evaluate the safety and efficacy of
its new micro crown orbital technology in treating severely calcified
lesions within the coronary arteries. This new system is limited by
federal law to investigational use and is currently not commercially
available in the United States or Japan.

Cardiovascular Systems, Inc.

Consolidated Statements of Operations

(Dollars in Thousands)

(unaudited)

Three Months Ended

Year Ended

June 30,

June 30,

2015

2014

2015

2014

Revenues

$

48,454

$

39,564

$

181,544

$

136,612

Cost of goods sold

10,873

9,115

39,520

31,041

Gross profit

37,581

30,449

142,024

105,571

Expenses:

Selling, general and administrative

38,270

33,727

143,684

117,994

Research and development

7,963

6,276

30,977

21,066

Total expenses

46,233

40,003

174,661

139,060

Loss from operations

(8,652

)

(9,554

)

(32,637

)

(33,489

)

Interest and other, net

(17

)

(74

)

(185

)

(1,801

)

Net loss

$

(8,669

)

$

(9,628

)

$

(32,822

)

$

(35,290

)

Net loss per common share:

Basic and diluted

$

(0.27

)

$

(0.31

)

$

(1.04

)

$

(1.25

)

Weighted average common shares used in computation:

Basic and diluted

31,752,184

30,959,038

31,547,711

28,295,758

Cardiovascular Systems, Inc.

Consolidated Balance Sheets

(Dollars in Thousands)

(unaudited)

June 30,

June 30,

2015

2014

ASSETS

Current assets

Cash and cash equivalents

$

83,842

$

126,592

Accounts receivable, net

30,830

21,383

Inventories

13,966

12,890

Prepaid expenses and other current assets

5,256

1,846

Total current assets

133,894

162,711

Property and equipment, net

32,883

15,297

Patents, net

4,511

3,823

Other assets

40

70

Total assets

$

171,328

$

181,901

LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities

Short-term borrowings

$

─

$

2,400

Accounts payable

9,763

9,703

Accrued expenses

20,125

17,626

Total current liabilities

29,888

29,729

Long-term liabilities

Other liabilities

2,005

117

Total liabilities

31,893

29,846

Commitments and contingencies

Total stockholders' equity

139,435

152,055

Total liabilities and stockholders' equity

$

171,328

$

181,901

Cardiovascular Systems, Inc.

Supplemental Sales Information

(Dollars in Thousands)

(unaudited)

Three Months Ended

Year Ended

June 30,

June 30,

2015

2014

2015

2014

Device revenue

$

42,988

$

34,906

$

161,280

$

120,414

Other product revenue

5,466

4,658

20,264

16,198

Total revenue

$

48,454

$

39,564

$

181,544

$

136,612

Device units sold:

PAD

11,379

10,525

44,191

37,873

CAD

2,377

822

7,289

1,385

Total device units sold

13,756

11,347

51,480

39,258

New customers:

PAD

45

54

217

208

CAD (1)

71

25

230

46

Reorder revenue %

96

%

98

%

96

%

97

%

(1) Prior periods have been adjusted to exclude accounts in the early
stage of product introduction and training.

Reconciliations of Adjusted EBITDA to the most comparable U.S. GAAP
measure for the respective periods can be found in the table on the next
page. In addition, an explanation of the manner in which CSI's
management uses Adjusted EBITDA to conduct and evaluate its business,
the economic substance behind management's decision to use Adjusted
EBITDA, the substantive reasons why management believes that Adjusted
EBITDA provides useful information to investors, the material
limitations associated with the use of Adjusted EBITDA and the manner in
which management compensates for those limitations is included following
the reconciliation table.

Cardiovascular Systems, Inc.

Adjusted EBITDA

(Dollars in Thousands)

(unaudited)

Three Months Ended

Year Ended

June 30,

June 30,

2015

2014

2015

2014

Loss from operations

$

(8,652

)

$

(9,554

)

$

(32,637

)

$

(33,489

)

Add: Stock-based compensation

3,679

3,246

14,718

10,928

Add: Depreciation and amortization

904

385

2,321

1,367

Adjusted EBITDA

$

(4,069

)

$

(5,923

)

$

(15,598

)

$

(21,194

)

Use and Economic Substance of Non-GAAP Financial Measures Used by CSI
and Usefulness of Such Non-GAAP Financial Measures to InvestorsCSI
uses Adjusted EBITDA as a supplemental measure of performance and
believes this measure facilitates operating performance comparisons from
period to period and company to company by factoring out potential
differences caused by depreciation and amortization expense and non-cash
charges such as stock based compensation. CSI's management uses Adjusted
EBITDA to analyze the underlying trends in CSI's business, assess the
performance of CSI's core operations, establish operational goals and
forecasts that are used to allocate resources and evaluate CSI's
performance period over period and in relation to its competitors'
operating results. Additionally, CSI's management is evaluated on the
basis of Adjusted EBITDA when determining achievement of their incentive
compensation performance targets.

CSI believes that presenting Adjusted EBITDA provides investors greater
transparency to the information used by CSI's management for its
financial and operational decision-making and allows investors to see
CSI's results "through the eyes" of management. CSI also believes that
providing this information better enables CSI's investors to understand
CSI's operating performance and evaluate the methodology used by CSI's
management to evaluate and measure such performance.

The following is an explanation of each of the items that management
excluded from Adjusted EBITDA and the reasons for excluding each of
these individual items:

-- Stock-based compensation. CSI excludes stock-based compensation
expense from its non-GAAP financial measures primarily because such
expense, while constituting an ongoing and recurring expense, is not an
expense that requires cash settlement. CSI's management also believes
that excluding this item from CSI's non-GAAP results is useful to
investors to understand the application of stock-based compensation
guidance and its impact on CSI's operational performance, liquidity and
its ability to make additional investments in the company, and it allows
for greater transparency to certain line items in CSI's financial
statements.

-- Depreciation and amortization expense. CSI excludes depreciation and
amortization expense from its non-GAAP financial measures primarily
because such expenses, while constituting ongoing and recurring
expenses, are not expenses that require cash settlement and are not used
by CSI's management to assess the core profitability of CSI's business
operations. CSI's management also believes that excluding these items
from CSI's non-GAAP results is useful to investors to understand CSI's
operational performance, liquidity and its ability to make additional
investments in the company.

Material Limitations Associated with the Use of Non-GAAP Financial
Measures and Manner in which CSI Compensates for these LimitationsNon-GAAP
financial measures have limitations as analytical tools and should not
be considered in isolation or as a substitute for CSI's financial
results prepared in accordance with GAAP. Some of the limitations
associated with CSI's use of these non-GAAP financial measures are:

-- Items such as stock-based compensation do not directly affect CSI's
cash flow position; however, such items reflect economic costs to CSI
and are not reflected in CSI's "Adjusted EBITDA" and therefore these
non-GAAP measures do not reflect the full economic effect of these items.

-- Non-GAAP financial measures are not based on any comprehensive set of
accounting rules or principles and therefore other companies may
calculate similarly titled non-GAAP financial measures differently than
CSI, limiting the usefulness of those measures for comparative purposes.

-- CSI's management exercises judgment in determining which types of
charges or other items should be excluded from the non-GAAP financial
measures CSI uses. CSI compensates for these limitations by relying
primarily upon its GAAP results and using non-GAAP financial measures
only supplementally. CSI provides full disclosure of each non-GAAP
financial measure

-- CSI uses and detailed reconciliations of each non-GAAP measure to its
most directly comparable GAAP measure. CSI encourages investors to
review these reconciliations. CSI qualifies its use of non-GAAP
financial measures with cautionary statements as set forth above.